The present invention relates to a circuit and a method of driving a plasma display panel to show images composed of odd and even fields, the plasma display panel having address electrodes and scan electrodes perpendicular to the address electrodes.
The present invention also relates to a device provided with a plasma display panel and control means coupled to the plasma display panel.
Such a method and device are known from EP-A-0 762 373. The known method discloses a plasma display panel of the ALiS (Alternating Lighting in Surface) type having scan electrodes and address electrodes. During an image cycle comprising two fields, each being divided in a predetermined number of subfields, each subfield having an addressing and a sustaining period, in a first (odd) field, for each subfield plasma cells associated with odd row electrodes are first addressed and then sustained, whereas, in a second (even) field, for each subfield, cells associated with even row electrodes are first addressed and then sustained. Thus, one frame cycle comprises two fields: one odd field in which for every subfield the cells associated with the odd electrodes are addressed and sustained, and an even field in which for every subfield the cells associated with the even electrodes are addressed and sustained. Consequently, two sustaining actions are required for each subfield, which takes a considerable amount of time.
It is an object of the present invention to provide a time-efficient method and device for performing scanning and sustaining.
To this end, the method according to the present invention is characterized in that both odd and even row electrodes, or vice versa, are addressed and subsequently sustained in the same frame.
It is an advantage of the method according to the invention that it provides a time-saving interlaced address and progressive picture sustain method, wherein, during each frame, all odd and even cells between the respective row electrodes are addressed and sustained. Consequently, one sustaining action per frame suffices for all rows, which saves one sustaining action per frame per subfield as compared with the prior art above. Thus, more light can be produced within a shorter time by said ALiS plasma display panel.
An embodiment of the method according to the invention is characterized in that, if one succession of odd and even row electrodes is addressed in a frame, the opposite succession of said row electrodes is addressed in an other frame. For example, in two successive frames, in the first frame, for every subfield, first the odd and then the even rows are addressed, then all rows are sustained, and in the second frame, for every subframe, first the even and then the odd rows are addressed, then all rows are sustained.
A particular selection of two address cycles from the four that the invention allows results in an equalization of the average amount of light produced in cells associated with odd or even row electrodes. If the odd row electrodes, followed by the even row electrodes are addressed in a first possible address cycle in a first frame, further referred to as odd frame, and the even row electrodes, followed by the odd row electrodes are addressed in a second frame, further referred to as even fame, then the negative effects of the order of addressing are compensated for, because these effects are averaged by the human eye. The same advantage holds for a second possible address cycle, wherein the even row electrodes, followed by the odd row electrodes are addressed in a first frame, and the odd row electrodes, followed by the even row electrodes are addressed in the second frame.
A further alternative embodiment of the method according to the invention is characterized in that the addressing is effected from top to bottom of the plasma display panel or possibly alternately from bottom to top. In particular, progressive addressing in odd frames is effected from top to bottom of the display panel, followed by sustaining, while progressive addressing in even frames is effected from bottom to top.
Consequiently, the device according to the invention is cbaracterized in that the control means are controlled such that, in a given frame, odd ones of the scan electrodes are addressed without any of the odd ones being sustained, and then even ones of the scan electrodes are addressed without any of the odd ones or the even ones being sustained, or vice versa, and subscquently the odd ones and the even ones are sustained.
In one preferred embodiment, if one succession of odd and even row electrodes is addressed in one of the frames, the control means causes the opposite succession of the row electrodes to be addressed in another one of the frames. According to another embodiment, the control means causes addressing to be alternated such that in one of the frames the addressing is effected from top to bottom of the plasma display panel and in the next one of the frames from bottom to top.
The method and device according to the invention will now be elucidated, together with their additional advantages, while reference is made to the appended drawings, wherein similar components are denoted by the same reference numerals. In the drawings: